| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem of a conventional ink jet image forming apparatus having a color recording head and a black recording head arranged in the moving direction of an ink carriage, that printing with black ink over the print with color ink to expedite drying of the black ink can be made only in unidirectional movement and the apparatus can not respond to bidirectional printing which enables execution of high-speed printing. SOLUTION: Color recording heads 3Y, 3M and 3C are disposed on the upstream side of a black recording head 3B in the carrying direction of a recording medium. According to this disposition, printing is made first with color ink by the color recording heads 3Y, 3M and 3C, on the recording medium being carried, and after the recording medium is carried by a prescribed amount thereafter, printing with slow drying black ink is made by the black recording head 3B so that it is put on the color-printed part. Accordingly, the printing with the slow drying black ink can always be made over the print with the color ink after the printing with this ink, irrespective of the moving direction of the ink carriage 1, i.e., in the bidirectional printing as well as in the unidirectional printing, and thus a drying time of the slow drying black ink can be reduced. |
